package collection;

import java.util.*;


public class ListDemo {
    public static void main(String[] args) {
        List <String> list = new ArrayList<>();
        list.add("one");
        list.add("two");
        list.add("three");
        list.add("four");
        list.add("five");
        System.out.println("list:"+list);

        String e = list.get(2);
        System.out.println(e);

        for (int i = 0; i <list.size() ; i++) {
            System.out.println(list.get(i));
        }

        Iterator<String> s = list.iterator();
        while (s.hasNext()){
            System.out.println(s.next());
        }

        for (String str : list){
            System.out.println(str);
        }
        System.out.println("-------------------------");

        //E set(int index, E e):将给定元素设置到指定位置
        //list.set(2,"six");   将下标为2的元素改为six
        String old = list.set(2,"six");
        System.out.println("list"+list);
        System.out.println(old);

        //E remove(int index):删除给定位置元素，并返回指定位置元素
        //list.remove(2):删除下标为2的元素
        String s1 = list.remove(2);//删除下标为2的元素，并将被删除的元素返回给s1
        System.out.println("list:"+list);
        System.out.println(s1);

        /*
        void add(int index,E e):
        将给定元素e添加到index所指定的位置，相当于插入操作
         */
         list.add(3,"seven");//相当于在list下标为3的位置插入seven
        System.out.println(list);//[one, two, four, seven, five]


    }
}
